Researchers of motor neuron diseases have long had a hunch that two fatal diseases, amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), might somehow be linked. A new study confirms that this link exists. "Our study is the first to link the two diseases on a molecular level in human cells," said Robin Reed, Harvard Medical School professor of cell biology and lead investigator of the study. The results will be published online in the September 27 issue of Cell Reports.